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Energy and Matter Chapter 2.
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Review! Easter Island: Colonized about 2,900 years ago Soil and tree resources exhausted (Natural Capital) Over 300 statues built to appease angry gods. War over remaining resources, cannibalsim.
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SCIENCE!
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Science Vs. Junk Junk science is untested ideas presented as sound science! How reliable are sources making the claim? Do they have an agenda? Are they experts? What is their source of funding? Do conclusions follow logically from the observations? Has the claim been verified by impartial peer review? How does the claim compare with the consensus view of experts in the field?
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Matter and Compounds Matter is anything that has mass and takes up space. Elements are specific atoms of a given type Compounds are forms when atoms of 2 elements form a covalent bond. –Ionic Compounds –Covalent Compounds
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Atoms, Ions, Compounds Atom: Smallest unit of matter that has characteristics of an element. Ion: an atom that has lost or gained an electron. –Cation: Positive charge –Anion: Negative charge When 2 ions form a bond, the result is a compound.
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Compounds and Formulas Each compound has a formula. –NO is Nitric Oxide. It is one Nitrogen and one oxygen. (Covalent) –KBr is Potassium Bromide and is one Potassium and one Bromine. (Ionic) Hydrocarbons are compounds with carbon and hydrogen, like methane (CH 4 ) Chlorinated Hydrocarbons are compounds of carbon, hydrogen, and oxygen atoms.
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Subatomics Each atom has a small nucleus and surrounding cloud of electrons –Electrons are negative –Protons are positive –Neutrons have no charge at all. Atomic number = # protons in nucleus (equal number of electrons…) Atomic Mass = #protons + neutrons
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Matter types
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Physical and Chemcial Changes Physical Changes do not change chemical composition. (melting, boiling) Chemical Changes do, and are the result of a chemical reaction. (Combustion, Decomposition)
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Law of Conservation of Matter When a chemical or physical change occurs, no atoms are created or destroyed. There is no away to “throw away” Undesirable, dangerous, or damaging chemical products are called Pollutants.
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Types of Pollutants The law of conservation of matter means that we will always have pollutants and must come up with a way to manage what we do produce. Persistence is a measure of how long the pollutant stays in the air, water, soil, or body.
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Types Degradable, nonpersistent: broken down completely or reduced to acceptable levels by natural processes. Biodegradable: Broken down by living organisms. Slowly degradable, persistent: Takes decades to degrade. Non-degradable: Cannot be broken down.
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